diff --git a/mlx/backend/metal/kernels/reduction/reduce_row.h b/mlx/backend/metal/kernels/reduction/reduce_row.h
index c8973429f..936d75bb5 100644
--- a/mlx/backend/metal/kernels/reduction/reduce_row.h
+++ b/mlx/backend/metal/kernels/reduction/reduce_row.h
@@ -224,7 +224,7 @@ template <
 
   if ((non_row_reductions < 32 && row_size <= 8) || non_row_reductions <= 8) {
     // Simple loop over non_row_reductions and reduce the row in the thread.
-    IdxT out_idx = tid.x + tsize.y * IdxT(tid.y);
+    IdxT out_idx = tid.x + tsize.x * IdxT(tid.y);
     in += elem_to_loc<IdxT>(out_idx, shape, strides, ndim);
 
     for (uint r = 0; r < non_row_reductions; r++) {